The present invention relates generally to a support structure for a coil mounted in a carriage of a magnetic disk drive or the like and, more particularly, to a support structure for reinforcing a thin carriage that is injection-molded integrally with a coil.
In magnetic disk drives, an actuator mounted with a voice coil is rotated to position a magnetic head to a predetermined position. The voice coil constitutes, with a voice coil magnet and voice coil yoke mounted on a base, a voice coil motor (VCM). A carriage assembly includes a carriage housing and the voice coil. The carriage housing includes a pivot hole, in which a pivot assembly is mounted, a mounting portion of a head gimbal assembly (HGA), and a holding portion of the voice coil.
In a relatively large magnetic disk drive, the voice coil is affixed with an adhesive to a carriage housing formed through casting. In this case, the carriage housing has a sufficient strength. There is therefore no chance that the carriage housing will be damaged during handling in an assembly process and that the voice coil will be mounted improperly. A carriage assembly adopted in a compact magnetic disk drive, however, includes a coil and a carriage housing that are integrally molded through injection molding of plastic. In such a carriage assembly, the injection-molded synthetic resin surrounds a periphery of the voice coil, leaving the voice coil exposed from both an upper and a lower surface.
FIGS. 1 and 5 of Patent Document 1 (Japanese Patent Laid-open No. 2005-93002) show a carriage that holds a voice coil. The voice coil has an outer peripheral surface and an inner peripheral surface surrounded by a liquid crystal polymer or other synthetic resin. The voice coil is thereby held by the carriage. Accordingly, an upper and a lower surface of the voice coil are exposed from the carriage.